Although often not visible, excavation on landmark sites or in buildings can directly impact a building’s physical integrity. Protecting historic buildings and sites is the basis for LPC’s rules for excavation (see LPC Rules, Section 2-16, available on our website, www.nyc.gov/landmarks).

Chapter 7

Excavation

Our goal is to help you submit a fully completed permit application for work that conforms to the LPC Rules so you can get your permit more quickly.

In This Chapter, You Will Find:

Section A How to Get Started

7.3

Section B LPC Rules and Criteria

7.5

Excavation Work – Protecting Historic Buildings During Construction – Facade Monitoring

7.6

Note: Excavation work must comply with Department of Buildings (DOB) requirements as well as with LPC criteria.

Note: If your excavation work is related to an addition or alteration in a yard or an areaway, refer to Chapters 6 and 8 for more information.

LPC Permit Guidebook · 7.2Chapter 7 · Excavation · In This Chapter, You Will Find: ·

Before applying for your permit, you should:

Section AHow to Get Started

Find Information about Your Building

This will help you determine how the rules apply.

What type of building is it? Search for the building on the Discover NYC Landmarks map. Click on your building to find construction date, architect and style, building and landmark type, and a link to the LPC designation report with historical background.

What did the building look like? Find historic tax photos from the 1940s and 1980s, available online through the NYC Department of Records & Information Services NYC Municipal Archives Collections. Additional information, including guidance on finding historic maps, can be found in the LPC Resource Guide Researching Historic Buildings in New York City, available on our website at www.nyc.gov/landmarks.

See If Your Work Requires an LPC Permit Maybe you don’t need a permit. LPC requires a permit for most excavation work, but a permit is not required for the following types of work:

Shallow regrading in yards to match or approximate existing grade.

Minor excavation in yards for shallow trenches or post holes.

Unsure whether your work requires a permit? Contact LPC at 212-669-7817 or info@lpc.nyc.gov.

LPC Permit Guidebook · 7.3Chapter 7 · Excavation · Section A · How to Get Started

A complete application requires all the materials listed below.

What You Will Need

□ An LPC Permit Application Form, filled out and signed by the property owner.

□ Color photos of the entire building and close-ups of areas of exterior excavation work.

□ Comparative drawings:

– Floor and / or site plans of existing conditions and locations of proposed excavation work

– Section of existing conditions and locations of proposed excavation work

You must also submit the following materials, unless the work requires only limited underpinning or no underpinning at all.

□ Pre-construction site survey to document existing adjacent conditions.

□ Structural conditions report that addresses the building’s age, original construction type, condition of foundations and facades, plus relevant site information (adjoining buildings, walls, etc.).

□ Two sets of DOB Support of Excavation (SOE) filing drawings.

□ In some cases, a facade monitoring plan. See Section B for more information. If LPC requires additional materials after your application is reviewed, you will receive a Materials Checklist from LPC staff.

Required Application Materials

LPC Permit Guidebook · 7.4Chapter 7 · Excavation · Section A · What You Will Need

The LPC Rules establish criteria that allow staff to review and approve proposals for certain types of work at landmark properties. Permit applications for work that meets the LPC Rules can be approved faster. If the work does not meet the rules, staff may suggest alternatives that do meet the rules — or your proposal may be presented to the LPC Commissioners for review at a public hearing. Staff can guide you through this process. Visit www.nyc.gov/landmarks for more information.

This section explains and illustrates the rules and criteria for the most common types of excavation work and how to protect your historic building during construction. See LPC Rules, Section 2-16, for more information.

Section BLPC Rules and Criteria

This is how the Landmarks Preservation Commission works:

In This Section: Excavation Work• Protecting Historic Buildings

During Construction

• Facade Monitoring

LPC Permit Guidebook · 7.5Chapter 7 · Excavation · Section B · LPC Rules and Criteria

Excavation WorkStaff can approve the following types of excavation work if it meets the following criteria: Lowering and replacing the lowest existing floor slab (e.g., basement or cellar) to increase floor-to-ceiling height to no more than ten feet.

Excavation to create a new crawlspace, cellar, or basement below an existing addition or new Commission-approved addition, if the depth does not exceed the lowest story of the original building.

Excavation for construction or repair of new structural elements, including footings, foundation walls, retaining walls, elevator and escalator pits, and other elements.

Excavation for construction or repair of new architectural elements, including light wells, stairwells, sunken terraces, in-ground pools, water features, planting beds, significant landscape features, significant regrading, and other elements, provided:

Work does not detract from the building or substantially eliminate the presence of a rear yard, and

At least a five-foot wide unexcavated planting area is maintained along the rear lot line.

A section drawing of a row house with an existing cellar floor-to-ceiling height of seven feet. The cellar floor slab may be lowed a maximum of three additional feet.

Excavation can be approved in a rear yard to accommodate a sunken terrace.

LPC Permit Guidebook · 7.6Chapter 7 · Excavation · Section B · Excavation Work

Protecting Historic Buildings During Construction

Your excavation work must be designed and executed in compliance with DOB regulations under the supervision of a licensed professional engineer or registered architect. Application materials must include a structural conditions report that demonstrates you have examined structural conditions and considered how to protect both the building and neighboring buildings.

Facade Monitoring For buildings six stories or less, you must include a plan for monitoring the facade of the building and adjacent buildings, if either of the buildings:

Were constructed before 1901;

Are constructed of wood;

Have an unreinforced masonry foundation, or

Have a stone or brick foundation affected by or adjacent to excavation.

If the work does not require underpinning or only requires limited underpinning and does not occur at or adjacent to designated buildings under the categories described above, facade monitoring is not required.

Underpinning in progress at the foundation wall of a historic building.

LPC Permit Guidebook · 7.7Chapter 7 · Excavation · Section B · Excavation Work